Piezoelectric-sensored sustainable pads for smart railway traffic and track state monitoring: Full-scale laboratory tests

Abstract

The present paper focuses on an initial assessment into the applicability of sensored sustainable pads, made from recycled polymers and embedded with commonly-accessible piezoelectrics. These sensing devices were used as smart rail pads and inside bituminous sub-ballast to monitor traffic and track state by measuring the stress variations in the components. A series of full-scale laboratory tests were carried out simulating train passage under diverse traffic scenarios and varying track section conditions in a testing box. Results indicated that the smart sustainable pads in both components showed the capacity to detect traffic load variations by measuring relative changes in signal amplitude of the sensor. Nonetheless, the smart rail pads presented higher accuracy to monitor axle loads, while the signals from the sub-ballast were influenced by the position of the sensor and so a higher potential to monitor track performance, rail-sleeper load distribution and detecting phenomena like hanging sleepers.